PID Control System Implementation

In this chapter, PI controller implementation is discussed for both current controllers as the inner-loop controllers, and velocity and DC voltage controllers as outer-loop controllers. In particular, the continuous-time controllers are discretized for digital implementation, and the operational constraints imposed by the PWM operations are taken into consideration in the implementation of the PI controllers. In order to avoid integrator windup in the presence of control signal reaching saturation limits, anti-windup mechanisms are proposed together with the digital implementation, which leads to the so called velocity form that has naturally embedded anti-windup mechanisms and is convenient for implementation. A MATLAB tutorial is introduced in this chapter to show how an embedded function can be created for the PI controller with its anti-windup mechanism.